An anticholinergic agent, glycopyrrolate, produced an increase in the fractional excretion of uric acid of greater than 20% in eight of 19 subjects with hyperuricemia or gout but in none of the 15 normouricemic control subjects. Glycopyrrolate placebo had no effect. A similar uricosuric effect was observed in several subjects following the administration of a second anticholinergic agent, tridihexethyl chloride, but not with the administration of a third agent, L-hyoscyamine. The uricosuric effect of glycopyrrolate and tridihexethyl chloride was not associated with a change in the binding of urate to plasma proteins in vitro. The autonomic nervous system may contribute to the regulation of uric acid excretion in some patients.